A backup script using bup.

backup.bup

#!/usr/bin/env bash

# Strict mode (see: http://redsymbol.net/articles/unofficial-bash-strict-mode/).
set -euo pipefail
IFS=$'\n\t'

# We name the repository directory after the system's hostname and the current
# year/month. We include the year/month combo so our backup repository doesn't
# continue to grow forever, and we can manually delete old ones as necessary.
name="$(hostname)"
repository_dir="$(dirname "${1:-}/gets-removed")"
repository="${repository_dir}/${name}/$(date -u +'%Y-%m')"

# Set the `bup` directory here so it affects all the `bup` commands.
export BUP_DIR="${repository}"

# Create the backup repository if it doesn't exist.
if [ ! -d "${repository}" ]; then
  bup init
fi

# Do the backup as non-intrusively as possible.
echo "Indexing ${name}..."
nice -n19 ionice -c3 \
  bup index \
  --exclude-rx='^/dev/.*' \
  --exclude-rx='^/proc/.*' \
  --exclude-rx='^/sys/.*' \
  --exclude-rx='^/tmp/.*' \
  --exclude-rx='^/run/.*' \
  --exclude-rx='^/mnt/.*' \
  --exclude-rx='^/media/.*' \
  --exclude-rx='^/var/lib/docker/devicemapper/.*' \
  --exclude-rx='^/var/cache/packman/pkg/.*' \
  --exclude-rx='.*/lost\+found/.*' \
  --exclude-rx='^/home/[^/]+/\.cache/.*' \
  --exclude-rx='^/home/[^/]+/VirtualBox VMs/.*' \
  --exclude-rx='^/home/[^/]+/\.config/[^/]*chrom[^/]*/Default/File System/.*' \
  --exclude-rx='^/home/[^/]+/\.config/[^/]*chrom[^/]*/Default/GPUCache/.*' \
  --exclude-rx='^/home/[^/]+/\.local/share/Trash/.*' \
  --exclude-rx='^/home/[^/]+/\.mozilla/firefox/[^/]+/Cache' \
  --exclude-rx='^/home/[^/]+/\.gvfs' \
  --exclude-rx='^/home/[^/]+/\.thumbnails/.*' \
  --exclude-rx='\.pyc$' \
  '/'

echo "Backing up ${name} to '${repository}'..."
nice -n19 ionice -c3 \
  bup save \
  --name="${name}" \
  --compress=0 \
  -vv \
  '/'